Fabric softener compositions provide benefits to treated fabrics, particularly in the last rinse phase of the laundry process, after the addition of the detergent composition in the wash phase. Such benefits include fabric softening, provided by the incorporation of fabric softener actives. However, there is increasing interest to reduce water and energy usage during the laundry process which can be achieved by lowering the number of rinse cycles. However, with a low number of rinse cycles, the deposition of fabric softener actives is reduced and hence the softening of the fabrics is less. Without wishing to be bound by theory, it is believed that this is due to the residual anionic detergent which remains in the last rinse. Cocquyt et al. (Colloids and Surfaces A: Physicochem. Eng. Aspects 298 (2007) 22-26) showed that anionic detergent can interact with the cationic fabric softener actives to form an insoluble complex. To prevent formation of such insoluble complex, hydrotropes can be added to the fabric softener composition to form a preferred complex between the anionic detergent and the hydrotrope. It is believed that such a preferred complex is formed when a hydrotrope is hydrophilic enough to not associate with the softener active vesicles but still hydrophobic enough to preferentially complex with the anionic detergent. Thus, the anionic detergent cannot interfere with the deposition of the softener active. However, it has been found that the addition of such detergent scavenging hydrotropes causes a drop in the viscosity of fabric softener compositions. Such a drop in viscosity can lead to consumer dissatisfaction as it can give the impression of a lack of “richness” of the formula. The drop in viscosity is particularly noticeable for fabric softener compositions comprising rheology modifiers such as cationic polymeric rheology modifiers. Such rheology modifiers are typically used to ensure phase stability, optimize the viscosity to connote richness of the formulation, and improve the pouring experience. The viscosity drop results in the need for an additional process step, whereby additional rheology modifier is post-added to restore the viscosity to the initial level. However, such a solution has several disadvantages related to increased manufacturing complexity. It requires an extra manufacturing step to add the additional rheology modifier. Furthermore, when other ingredients of the fabric softener composition are changed or different levels of hydrotrope are added, the viscosity drop will vary. As a consequence, several iterations may be required to determine the level of additional rheology modifier needed to restore the viscosity to the target level.
Hence, there is still a need for a fabric softener composition with a rich appearance comprising a fabric softening active which exhibits improved viscosity stability upon the addition of detergent scavenging hydrotrope without increasing manufacturing complexity.
WO2008/076753 (A1) relates to surfactant systems comprising microfibrous cellulose to suspend particulates. WO2008/079693 (A1) relates to a cationic surfactant composition comprising microfibrous cellulose to suspend particulates. WO2015/006635 relates to structured fabric care compositions comprising a fabric softener active and microfibrillated cellulose. WO03/062361 (A1) discloses liquid fabric conditioners comprising cellulose fibers and esterquats. WO2010003860 relates to liquid cleansing compositions comprising microfibrous cellulose suspending polymers. WO02092742 (A1) relates to fabric softening compositions, preferably translucent, clear or transparent conditioners, which in addition to a cationic fabric softener comprise a fabric co-softener, and a hydrotope. WO2016/014733 (A1) relates to treatment compositions comprising a polymer system and a cationic hydrotrope.